1. Field
The present invention relates generally to high-G shock testing machines, and more particularly to low-cost, reusable, “pseudo-static” testing machines and methods capable of imposing high acceleration and deceleration (>±10,000 g), opposing loads to a large (10-100+ lbs.) payload that are sustained over long durations (>5 msec). Such machine would provide the means for testing ordnance and commercial products/components under multi-axial loading, which includes both bending and shear moments. This includes the most extreme example of such events, namely “tail slap”, where large lateral accelerations are introduced due to the bending and rebound of the product/component in the lateral direction, e.g., in the case of ordnance, perpendicular to the axis of penetration.
2. Prior Art
Gun-fired munitions, mortars and rail-gun munitions are subjected to high-G (setback and set-forward) acceleration during launch and target impact. Similar but more complex combinations of axial as well as lateral and bending shock loadings are experienced by air dropped weapons as they impact the target, particularly when the weapon is rocket assisted to achieve high impact velocities and when the target structure is highly heterogeneous, such as reinforced concrete or soil with large rock content. As a result, all components of the system and the system itself must survive such shock loading events and be qualified to such severe environments.
Developing a controllable test method and predictive capability to apply this environment in testing is critical to the development of fuze, energetic, and other weapon technologies. However, the corresponding change in velocity typically requires ballistic or operational testing. Both testing methods are extremely costly, personnel intensive, and introduce both technical and safety risks.
The vast majority of aircraft and satellite components, whether military or commercial, must be tested under certain shock loading conditions. That is, aircraft components must be shock tested to ensure that their design will survive its intended environment. Consequently, different aircraft components may have widely varying shock testing requirements. Currently, there is no one shock testing apparatus that can shock test aircraft components to accommodate the varying shock testing requirements for aircraft components, if at all. Thus, the industry resorts to building specialized shock testing machines or using computer simulation for shock testing, methods which are expensive and/or inaccurate.
In addition to rigorous vibration profiles, many consumer electronic components must be shock tested to determine how they will perform under certain shock conditions. Electronic components are often shock tested to determine how they will survive under unintended conditions, such as repetitive dropping. Of such consumer electronic components, device casings and circuit boards are often shock tested to determine survivability due abuse while other electronic devices are designed for heavy duty usage, such as in the construction trade and must be shock tested to determine if they are fit for their particular harsh environment. The current shock testing methods for consumer electronic devices have the same shortcomings as those described above with regard to commercial aircraft. Current shock testing machines in the consumer electronics area are either very simple drop testing from heights or pneumatic shock machines, both of which are inaccurate and their repeatability is unreliable.
Automobile components (as well as light and heavy duty truck components) must also undergo rigorous shock testing under normal use as well as components which can fail during a crash. Some automobile components must undergo shock testing to determine how they will perform under normal conditions, such as some structural frame components while other components must undergo shock testing to determine their performance during a crash, such as electronic components, steering wheels, airbags and the like. Like other shock testing machinery currently available in the areas of commercial aircraft and consumer electronics, the shock testing of automobile components are inaccurate, their repeatability is unreliable and they can also be relatively expensive.